An Introduction to Train Brakes
Ponder the amount of energy that an ordinary freight trains possesses as it rolls down the
tracks at 70 M/H. Trains carry enormous amounts of cargo at great speed
on a daily basis. The brake systems of a freight train is examined in
this introductory article by John Bentley

Automotive Black Box Data Recovery Systems
Black Boxes are commonly used to aid the investigators of air crashes.
Do automobiles have the equivalent of a black box? Is the data accessible to a
collision investigator? Don Gillman explains one such system, its
capabilities and limitations.

Injury Mitigation Devices
This well illustrated article is a good introduction to the topic of seat belts.
Basic seat belt concepts, an explanation of how they function, and terminology are covered in this
submission by Ed Phillips

Sensitivity to Uncertainty Reconstructionists
routinely measure some variable, plug it into an equation and solve for some unknown. Was the
measurement exact?. Of course not. It had some error. The amount of error is called
uncertainty. How uncertainty affects a result calculated in an equation is explored in this article by
Dr. Oren Masory and Bill Wright.

Error Analysis for Three Different Methods
Of Determining Drag Factor Three different methods for determining drag factor
are examined from an error analysis perspective. Depending on methodology, there is
great variability in the resulting numbers. This article offers the step by step
calculations for determining error in Skid Tests, Drag Sled tests and Accelerometer
equipped vehicles. Dr. Oren Masory and Bill Wright.

TAR Library List UPDATED 7/98 A reconstructionist spends a
lifetime building a library of reference material. This list compiles standard works that would likely
be included in just such a complete library. Please take the time to add your favorites to
this list. The list was compiled by R.W. Bob Rivers.

Three Point Airborne Trajectory Analysis
When all the information is available airborne equations are capable of returning
speed estimates of a fine tolerance. Unfortunately an investigator is usually not
able to collect all the information necessary for these calculations. As a result
he is forced to use an airborne equation to range estimates, or seek a minimum estimate.
Andrew Rich offers an approach to make fine tolerance speed estimates from an
otherwise incompatible situation.

Proposed Extensions to Federally Mandated Bumper Testing
Hundreds of Federally Mandated Bumper Tests have been conducted. The tests are conducted
with a rigid wall or impactor. This paper proposes methods by which the existing
tests could be extended to yield additional design and analysis data that could be
used to help design lower vehicle compartment loadings. Dr. Irving O. Ojalvo and
Dr. Orem Masory

The Importance of the Weight Distribution of a Vehicle
During Braking It is common practice to assign static weight distributions to work
done by a skidding tire. If one front tire carries 30 % of the vehicles weight at rest, that skidding
tire must do 30% of the work while skidding right? Not necessarily. This question is explored by
Dr Bruno Schmidt.

TAR Library List A reconstructionist spends a lifetime building
a library of reference material. This list compiles standard works that would likely be included
in just such a complete library. The list was compiled by R.W. Bob Rivers.

Least Squares Method
of Line Fitting Experiments are usually conducted find or validate mathematical
models. These models are used to find unknown quantities in applied problems or predict future
test results. The Least Squares method of line fitting is a way of developing mathematical expressions
from experimental data. This procedure is explained and demonstrated in an article by Dr. Bruno
Schmidt

Accessing NHTSA's Crash Test Database NHTSA
has crash tested thouands of vehicles. Where is the data? It is here online, if you know how to
access it. In a web "how to" article Tom Langley explains the procedure to get at this
wealth of information.

Evidence of ABS Scuffmarks on the
Roadway. A group of South Florida accident investigators conduct an ABS
workshop.Skidmarks and ABS scuff marks are generated on various surfaces, then examined, to
develop a strategy for finding this evidence at future collision sites. This article contains
additional documentation and previously unpublished photos. Bill Wright

This
is a Portugese translation and technical adaptation of a TARO article that details the Evidence of ABS Scuffmarks on the Roadway. Are you bi-lingual?
TARO will gladly make space available for translations of this and other Traffic Accident
Reconstruction related articles.

CARP 1.04 Computerized Accident Reconstruction
Programs
Where did all the DOS based 80286 computers go? Many are still out there languishing for
software. J.F. Mitchell makes his original program CARP 1.04 available for free.
This metric program includes basic and advanced Accident Investigation formulae.

Stiff1: Stiff1 is a small downloadable Windows
compatible program. Give the program barrier crash data and it computes the stiffness constants.
James Perry

iCAR V 2.4: iCAR is a comprehensive
menu-driven
traffic accident reconstruction application. It performs the calculations necessary for most
reconstructions. iCAR is offered, free of charge, by its author James Perry

Basic Accident Investigation Manual Many
TARO readers are involved in accident investigation training. This is an accident investigation
training manual that covers all basic AI topics. It is offered to the public domain by its author
Luis Martinez.

Renfroe Engineering
Technical Papers David A. Renfroe and his firm, Renfroe Engineering, is a significant source
of vehicle dynamics, off road vehicle, and occupant restraint research and publishing. The Renfroe
website offers several related techinical papers.

Speed From Skids: A Modern
Approach
This full 'net reproduction of SAE 950354 discusses modifications to the basic "Speed from Skid mark"
equation. The kernel in this different approach centers on estimating work done by braking tires prior
to the point visible skid marks are observed. This article is in Adobe Acrobat format
(Get Adobe Acrobat Reader)
. It is authored by James Neptune, James Flynn, Philip Chavez and Howard Underwood.

A Method for Quantifying Vehicle
Crush Coefficients This 1992 paper offers a method for calculating vehicle
crush coefficients from NHTSA Vehicle Crash Test Data Base. Of course this data-base is now
available online. Though now several years old this paper offers a excellent history of speed
from crush concepts. This article is in Adobe Acrobat format. James Neptune, George Blair,
James Flynn

IUN/FYDE Introductory Physics
Notes These WWW pages constitute a general, non-calculus introductory physics course. They are
based on lectures given through the IUN/FYDE distance education program of the University of
Winnipeg.

Temporary Brake Failure, It is Possible?
Would you believe a person that told you his brakes failed causing a collision when they work
well in a post collision inspection? A technical paper discusses this issue.Wade Bartlett

Vector Momentum Analysis An excellent
introduction and discussion on momentum collision analysis. The article has many illustrations and much
support for a graphic understanding of momentum. George M. Bonnett

Collision Times Four A simple "thought
experiment" sheds light on the relationship between energy, work, and momentum.
Understand this example and it will serve you as a convenient reminder for the rest of your life.
George M. Bonnett

ACTAR ACTAR is online.
Of interest are its history, the ACTAR Newsletter and CEU information.

Compute A Crash Ed
Livesay offers an original piece of accident reconstruction software. It is well written and offers
much in the way of user support and error checking.

Human Error in Road Accidents: An Information Processing Analysis
This article provides a brief overview of human information processing
limitations and explains how they can contribute to road accidents. This is a
"first-principles" approach to accident investigation because it draws on knowledge of
basic human psychological processes. Instead of looking at the driver from the outside,
we try to understand his/her mental processing and how it interacts with the
environment. Marc Green, Ph.D. John W. Senders, Ph. D

Human Factors - Perception &
Reaction : How reliably can a reconstructionist estimate a reaction time?
What about the calculations based on this reaction time? Is reaction time
influenced by the time of day or available light? These and other factors are
examined in an article by Joseph E. Badger.

SMAC-97 Refinement of the Collision
Algorithm
"This page is the text of the presentation on February 27, 1997 by Brian G. McHenry of the paper "SMAC-97
- Refinement of the Collision Algorithm", SAE Paper 97-0947". Does a computer model always fit? Do we
know when it doesn't? Brian McHenry

Torque and Horsepower - A
Primer This is a common experience essay, in hot rod terms, on the difference between
power and torque. Fundamental units are lightly treated. Bruce Augenstein

The Effects of Grade on Kinetic
Friction Accident investigators routinely adjust level friction values with the tangent (slope) of
the angle traveled by the sliding vehicle. Is this a valid adjustment? The relationship is derived in a
technical paper at REC-TEC's site.George M Bonnett, J.D.

Understanding Delta V from
Damage A introduction, history and discussion of crush and why it is important to the
accident investigator. The article contains numerous charts, illustrations and graphs.George M
Bonnett, J.D.

Bowling's Automotive
Programs A grab bag of online java scripts for the automotively bent engineer. Of
specific interest is a routine that calculates a tire's effective rolling
diameter and another that finds engine R/M from M/H.Algorithms are offered for most
routines.Bruce Bowling

Manual of Traffic SignsRichard Moeur is a engineer with the Arizona Departmant of Transportation. His web page offers
general observations on the subject of Traffic Control Devices. Contained in other portions of
this page are a good representation of a Traffic
Engineer's Ramblings.

N T S B Aviation Accidents NTSB aviation
investigations occasionally get intense media coverage. These major incidents represent only a small part
of their workload. This page links down to summarys of 37,000 investigations they have conducted since
1983. These reports are an interesting perspective for the reconstructionist.

NHTSA Compliance Test
Procedures The Office of Vehicle Safety Compliance (OVSC) provides contracted laboratories with
Laboratory Test Procedures (TPs) which serve as guidelines for obtaining compliance test data. The data
are used to determine if a specific vehicle or item of motor vehicle equipment meets the minimum
performance requirements of the subject Federal Motor Vehicle Safety Standard (FMVSS). This page offers
some of these TPs.Note: Many of these procedures are only down loadable as a Word
Perfect Document.

Bureau of Transportation Statistics : BTS is an arm of
the US Department of Transportation charged with "improving public awareness of the nation's
transportation system and its consequences". This site offers a great deal of general transportation
information, and is searchable.

SAFER The Safety and Fitness Electronic Records
(SAFER) System is planned as a component of Intelegent Transportation System. SAFER will provide carrier,
vehicle, and driver safety and credential information to fixed and mobile roadside inspection stations.
The FHWA Office of Motor Carriers has provided carrier safety data to industry and the public for many
years via telephone requests and paper reports. The SAFER System makes it possible to offer this
information electronically. Limited SAFER functions are now provided free of charge over the Internet.

Sisters and Clones This
Adobe Acrobat document has general vehicle information on most vehicles manufactured from 1980 to date.
Included in this list is information on ABS availability, frame construction, drive axle, body styles, and
"sister" vehicles offered by other companies under the same manufactuting parent company. This list is
offered by George Scalia of Scalia Safety Engineering. It of offered free on the Neptune Engineering
website.

Euclid's
Elements One of the five most popular books of all time. This website presents this
foundation of science in a WWW java enhanced enviornment. The page is the work of D. E. Joyce

Alignment Methods Author Mike
Piera offers techniques for checking and adjusting automotive front end alignment. Though these
adjustments are offered on a obscure car (Porsche 911), many of these same measurement methods are
applicable to a first order post collision vehicle inspection.

SAE: The Engineering Society for Advancing Mobility Land
Sea Air and Space ® . The site features general information about the societiy's purpose,
membership information and a calendar of events. A search capability accesses an impressive list of SAE
technical papers.

The Insurance Institute for Highway Safety: IIHS
is a nonprofit, scientific, educational organization dedicated to reduction of losses on the highway.
IIHS's current web page has a distinct consumer slant. The page has been online only a few months and
offers a minimal search capability. IIHS now makes makes
most of its publication Status Report available online.

The Highway Loss Data Institute: HLDI is an
organization supported by IIHS dedicated to publishing data on the way insurance losses vary by vehicle
type. This site offers searchable access to the same IIHS database.

Goodyear Tire and Rubber Company has a page that is
primarily oriented toward the consumer. There is basic information available on chassis alignment, tire
wear, tire sizing, and tire grading at the ISO 690-2, Bibliographic
references to electronic documents A well defined standard exists for quoting a paper document in
a bibliography. How do you quote an electronic document? This is the International Organization for
Standardizations (ISO) current recomendation.

Alldata: Alldata Corporation
is the leading publisher of Electronic Automotive Diagnostic and Repair Information. The Alldata
web site offers searchable access to Safety Recalls, General Recalls, and Technical
Service Bulletins.

Car and Driver : The print magazine Car and
Driver has a WWW presence. Of interest to the reconstructionist is The Daily Insider. The Daily Insider reports
on late-breaking automotive news. Also of interest the Buyers Guide offers basic vehicle information
(wheelbase, track and weight) for many late model vehicles. To retrieve this information, search the
vehicle in question then click on STATS at the bottom of the page.

The Physics of Auto
Racing. Frequently a car involved in a collision is operated at the limit of its performance
envelope for a few seconds. Race cars operate at this limit on a continuous basis. In a series of
articles, Brian Beckman explores the consequences of operating at the edge. These articles are an
interesting perspective on the commonality of science. Auto racers and accident reconstructionists are
really talking about the same thing. Brian Beckman.

AutoWare
AutoWare is a small software development company that produces racecar applications.
Their web site contains some simple and short articles that should be of interest
to the reconstuctionists. Among them are the following topics:

The Interactive
Textbook for 1996: This is a WWW college level physics class and texbook. The course includes lecture notes to assist in the
understanding of topics presented in the text. This course is offered through the University of
Pennsylvania. It is the work of Dennis DeTurck, Larry Gladney, and Anthony Pietrovito.

Net Science Three exceptional High School
students have put together a simple, short and easy to read 'online' Physics course. This course is a good
place for the informally trained accident investigator to start. Its simplicity and fresh examples will
also amuse the trained veteran. The few non-critical errors on these pages are worth overlooking.

Glenbrook South High School
"Physics Classroom" This is a particularly well executed online physics class. It is geared for a
student without a calculus background. The page has many examples and interactive problems. The page is
offered by Glenwood South High School in Glenwood, Illinois USA.

Automotive Learning Online A particularly
clever use of java scripts that teach basic concepts. Have you ever wondered just how spider gears allow a
differential to drive axles at two different speeds? An animation here will demonstrate. This site is made
available by Information Graphics Company.

The Skeptical Inquirer: It is the business of
accident reconstructionists to draw conclusions. A crucial part of this process should be "the critical
look." The Skeptical Inquirer examines the fringes of popular science and applies this critical look. The
topics are not accident reconstruction, but the process serves as a good model for a well considered
conclusion.

Yahoo's Government Index The Yahoo Search
index of Web government resources. This index includes most of the Web pages contained in Fedworld, but
also offers state Web resources. Many of these contain links down to county and city Web sites.

The Internet Roadmap Still a
little confused about just what the Internet is? This is a general overview of what's out there and how to
use it. Patrick Crispen